This invention relates to a programmable thermostatic control and energy management system which is constructed, for example, to replace conventional thermostatic controls in a residence and is used to control the temperature at the measurement situs in accordance with the programmed requirements of the user and also to shed energy usage in accordance with the programmed requirements of the user to lower energy usage.
Conventional thermostats located in rooms where the temperature is to be controlled are commonly connected via two leads (heating) or four leads (heating and cooling) to a furnace and/or an air conditioner. These thermostats have dials or other means for setting the desired temperature level and in addition have switches for switching to a heating mode or a cooling mode. When the actual room temperature falls below the minimum temperature setting and the thermostat operating in a heating mode, a heating unit is activated and when the actual room temperature rises above a maximum temperature and the thermostat operating in a cooling mode, the cooling unit is activated. Such conventional thermostats may be of the analog type which employ a mercury thermostat or a bi-metallic strip to measure and display the temperature or may be of the digital-type which employ a digital temperature transducer to display the temperature in a digital format and control the temperature through digital circuitry. These systems, conventionally, are for temperature control only and do not have energy management capabilities.
A programmable thermostatic control is described in U.S. Pat. No. 4,071,745. This control is connected to a temperature sensor located at the place the temperature is to be controlled. A user may program the programmable control unit to activate heating or cooling systems to provide thermostatic control at the sensor location according to the user programmed temperature settings. With this programmable control, a user has the capability to program different temperature levels for different times of the day such as hour by hour.
Another programmable thermostatic control is described in U.S. Pat. No. 3,964,677. This control includes digital counting circuitry for controlling the temperature of an area for at least two different selected temperatures at selected times and for selected periods. This control can be used to replace conventional thermostats and installed without modifying existing wiring. Furthermore, the control is operated from the electrical power supplied from a conventional furnace power supply.
U.S. Pat. No. 4,079,366 describes an electronic programmable clock timer which can be used to control heating and cooling for selected periods of time and for controlling other electrical functions such as lights for selected periods of time.
Honeywell, Inc. is presently marketing a Microelectronic Fuel Saver Thermostat under the tradename Honeywell T800. This unit is described in the copyrighted Honeywell, Inc. publication No. 50-6681. This device is a programmable thermostatic control installed at the location where the temperature is to be controlled and utilizes existing thermostat wires to control the heating and cooling systems. With this device, the thermostat may be programmed for once-a-day or twice-a-day setback/set up and may be set to automatically skip the daytime program on two days such as weekends to further conserve energy.
Power management systems are also known such as the IBM Facility Control/Power Management System described in IBM Booklet No. GH30-0094-0. This System, which because of its size and complexity is generally used in large commercial or industrial applications, utilizes an IBM Series/I Computer to conserve energy by lowering power loads and reducing demand peaks. With this System, energy using units such as heaters, fans, pumps may be shut completely off to reduce energy usage when certain programmed threshhold levels are reached or the system may be used to shed energy through staging. All of this may be accomplished within selected control periods during the day which may range from minutes to hours during any 24-hour day.